Can mammograms increase cancer risk for some women?

As women are still struggling to make sense of the new mammogram recommendations released in November by the U.S. Preventive Services Task Force, research presented today at a meeting of the Radiological Society of North America suggests that, for women at high risk of developing breast cancer, who are often urged to undergo annual screenings beginning at age 25, exposure to radiation through mammograms may actually be harmful.

This research is preliminary and future analysis is essential to bear out the findings, but it is particularly concerning because it suggests that women at highest risk, who are in most need of screening, may be the most vulnerable to the radiation in mammograms. In the review of six studies that included roughly 5,000 high-risk women, who have an increased likelihood of developing breast cancer due to genetic reasons or family history, for example, researchers found that high-risk patients who were exposed to radiation were 1.5 times more likely to develop cancer than high-risk patients who had no exposure. High-risk patients who had greater levels of exposure to radiation—either beginning mammograms before age 20, or having five or more exposures—were 2.5 times more likely to develop cancer.

Researchers say that the findings may suggest the need for a change in screening methodologies—using ultrasound or MRI more frequently for certain patients, for example. Yet, simply opting for alternative screening methods may not be the best approach—MRIs tend to be more expensive and yield more false positives, for example. Instead, suggests Dr. Robert Smith, physicians should use a combination of both MRIs and mammograms for the best cancer detection results. As he told the New York Times:

“It’s not as if clinicians are unaware and unconcerned about radiation risks in young women,” he said. “If mammography offered no advantage, they wouldn’t do it.”